Interpretation No. 2008 – Shower Pan Material and Installation Standards

Manual Reference Section: 2
Applicable Code: BC Plumbing Code (1998), Part 7, Section 7.2
Status: Approved by LMPCC

Background

The Plumbing Officials’ Association of British Columbia issued this interpretation to resolve recurring questions from inspectors and contractors regarding acceptable materials and proper installation practices for shower pans. Enquiries had been received from both residential and commercial project sites, where differing approaches to shower receptor construction had led to inconsistent enforcement across jurisdictions. The ruling established a uniform position on material selection, workmanship standards, and post-installation testing.

Subject Matter

The enquiry addressed whether certain sheet materials and prefabricated receptors met the standards referenced in the BC Plumbing Code for shower pan assemblies. Specific questions arose about the suitability of chlorinated polyethylene (CPE) and polyvinyl chloride (PVC) sheet liners in site-built shower installations, as well as the acceptability of one-piece moulded receptors manufactured to CSA B45.5 (Plastic Plumbing Fixtures). A further concern related to the proper method of sealing sheet liner edges at wall junctions and around the drain fitting.

Ruling

The Association confirmed that shower pans constructed using sheet-applied membrane liners must employ materials conforming to the applicable CSA standards for the product type. CPE and PVC sheet membranes were accepted provided the liner thickness, joint methods, and corner treatments satisfied manufacturer installation specifications and the requirements of the authority having jurisdiction.

Prefabricated shower receptors were required to comply with CSA B45.5 for plastic fixtures or CSA B45.1 for ceramic units. Installation of these receptors had to follow the manufacturer’s documented procedures, including provisions for structural support beneath the receptor base.

For site-built shower assemblies using sheet liners, the membrane was required to extend a minimum of 50 mm above the finished dam or threshold height at all points. Penetrations through the liner at the drain connection had to be made using a clamping ring assembly compatible with the membrane material, producing a watertight seal without reliance on adhesives alone.

Testing Requirements

All shower pan installations, whether prefabricated or site-built, were subject to a water test before concealment. The test involved filling the receptor to the level of the dam or threshold and maintaining that water level for a minimum period sufficient to confirm the absence of leakage. The inspector was required to verify the test before wall finishes, tile, or other coverings were applied over the pan assembly.

Scope of Application

This interpretation applied to new shower installations in residential dwellings and commercial buildings throughout British Columbia. It did not address the structural substrate or waterproofing of surrounding wall assemblies, which remained subject to the applicable provisions of the BC Building Code.